Everyone can die, and peoples survival depends on your interactions with them. (Like Mass Effect 2) Clem's survival depends on how you've raised her, Kenny's survival depends on your relationship with him, etc ,etc, and YOUR survival depends on how people see you as a person.

I don't know how it will end, but I would LIKE to have Carly, Ben, Clem and Lee together fighting it out against the world. They would probably settle in a secure compound somewhere, so that they can regroup and thrive.

I know for sure that in they go to Savannah. Probably in the last episode, they find Clem's Mom/Dad zombified. I tries to attack Clementine, but Lee saves her. Then, he grabbes his gun, and shoots the walker, in mercy. It's an hearthbreaking moment, while Clem cries, and you try to calm her down.